The EU Horizon 2020-funded SEA-TITAN project continues to make strong progress in the development of an innovative next-generation Power Take-Off (PTO) solution.

The system is designed to reduce the life-cycle environmental impact and technological risks associated with developing wave energy generation technology, and significantly increase technology performance.

The SEA-TITAN project is a Spanish-led initiative that aims to achieve a ‘step change’ in the wave energy sector by designing, building, testing and validating an innovative direct-drive Power Take-Off (PTO) solution - called an Azimuthal Multi-translator Linear Switched Reluctance Machine (AMSRM) - to be used with multiple types of wave energy converter. In doing so, the project team aims to achieve high continuous and peak force densities, as well as high efficiency levels applicable to multiple wave energy conversion technologies, through collaboration with a number of wave energy developers and industrial partners with a strong track record in the sector.

As Aleix Maria Arenas, Project Manager at SEA-TITAN coordinator Wedge Global, explains, the AMSRM solution is based on a new configuration and geometry of the first-generation W200 – a Rectangular Multi-translator Linear Switched Reluctance Machine PTO deployed alongside the novel W1 wave energy converter and a heaving point absorber by the SEA-TITAN coordinator, Wedge Global, at the PLOCAN test site in Gran Canaria in 2014.

“During these sea trials, over 3,000 hours of operational data was obtained, and important hydrodynamic and overall performance parameters were validated,” says Arenas.

“From the early stages of the PTO development, the team was aware of the importance of achieving high force densities in the generator and this concern led them to develop the concept of a Multi-translator Linear Switched Reluctance Machine, a patented novel idea that allows a significant increase in force density,” he adds.

Although different wave energy technologies harvest wave energy in a variety of ways, PTO devices are generally responsible for converting this energy into electricity, typically via a pneumatic-electrical, hydraulic-electrical or mechanical-electrical process. Such conversions can also be further simplified by using a linear electric generator and a direct-drive PTO system. As Arenas explains, direct-drive PTO solutions are viewed as very attractive because they avoid the need to for intermediate stages when converting wave energy to electricity - eliminating common failure sources such as those that might occur in hydraulic or mechanical components.

“They also improve the overall efficiency of the facility and increase the overall controllability of the WEC since modern power electronics and control systems greatly improve the performance of all electrical machines - a point that is becoming increasingly important because it allows the implementation of more efficient strategies to increase the energy that can be harvested from the waves,” he says.

According to Arenas, the key advantage of the SEA-TITAN PTO is that the novel azimuthal topology ‘enables more compact and efficient PTOs, increasing the amount of energy that can be extracted from the sea waves with smaller, cheaper and easier to maintain wave energy converters.’ Arenas also reveals that the SEA-TITAN team has successfully completed the modelling and design project phases - resulting in a complete software simulation tool called a ‘wave-to-wire model’ and a complete set of fabrication drawings and bill of materials for fabrication - and has now moved on to the fabrication and testing phases.

Although all activities up to this point have been carried out by consortium partners – including Wedge Global, CorPower, Centipod, HydroCap, OCEM, Columbus, ENGIE, EDP CNET, CIEMAT, WAVEC and UNE – Arenas reveals the team will also work with Siemens-Gamesa throughout the fabrication phase.

“We started this collaboration in the first quarter of 2020, but have sadly been delayed due to the COVID-19 impact on access to industrial facilities and reduced operating staff,” he says.

“We are still working on the manufacturing process at steady pace but are still somewhat worried by the ‘second wave’ of COVID-19. If we don’t face any additional impacts, we expect to receive the new prototype for testing by mid-January 2021,” he adds.

By Andrew Williams